The present invention relates to an assembly constituted by a drill and a tenon for anchoring a dental prosthesis adapted to be fixed in the root of a tooth.
Anchoring tenons are known at the present time which are made in different shapes, namely cylindrical, cylindroconical, conical or stepped conical. Each of these types of tenon has advantages and drawbacks.
In particular, Patent No. FR-E-80794 describes an anchoring tenon constituted by two coaxial cylindro-conical parts of different diameters, the cylindro-conical part of smaller diameter itself being extended by a cylindrical end part. Such a tenon is positioned in a hole pierced by means of a drill having a profile identical to that of the tenon but of a slightly larger diameter at all points along the length of the tenon. Once positioned in the hole drilled in the root of a tooth, the cylindrical end part of the tenon stops at a certain distance from the bottom of the hole. Such a tenon presents the drawback that it "floats" relatively in its hole and it tends to move out by itself, when silicon is injected for taking an impression, under the effect of the pressure of this silicon injected by means of a syringe. To ensure a firm hold of the tenon in its hole, it is necessary to place circlips in transverse annular grooves in this tenon, which ensure compensation of the clearance. Consequently, such a tenon has a relatively complex structure and is therefore relatively expensive to manufacture; furthermore, it does not enable a strictly calibrated thickness of the layer of sealing cement interposed between each of the cylindrical parts and the wall of the drilled hole to be obtained.